1. Technical Field
The present invention relates to filter units, liquid ejecting apparatuses, and bubble removal methods.
2. Related Art
An ink jet printer (called a “printer” hereinafter) that ejects ink (a liquid) from nozzles provided in a head is known as one example of a liquid ejecting apparatus. In such a printer, the ink is ejected from the nozzles by applying pressure to ink within ink chambers that communicate with the nozzles and that are filled with the ink. If bubbles become intermixed with the ink within the head, pressure cannot be properly applied to the ink, and ejection problems and the like occur as a result.
Accordingly, there is a printer in which a filter is provided within the head; in a printing mode, the filter catches bubbles that have intermixed with the ink, whereas in a maintenance mode, the bubbles pass through the filter, and the bubbles are then discharged to the exterior of the head. Furthermore, a printer has been proposed in which a bubble catching unit is provided so that bubbles make contact with a filter and a set region of the filter is kept in a blocked state, so that it is easier for the bubbles to pass through the filter during the maintenance mode (for example, see JP-A-2007-313703).
However, fine bubbles do not easily flow with the current of the ink, and do not easily come into contact with the filter if the fine bubbles rise due to buoyancy; accordingly, there has been a problem in that such fine bubbles have been unable to pass through the filter during the maintenance mode, and have remained within the filter unit. Particularly in the case where maintenance that ejects ink from the nozzles is executed by applying pressure to the ink within the head, the bubbles are compressed and shrink, which causes even more bubbles to remain within the filter unit.